The present invention relates generally to mold forming apparatus and more particularly to a device for the production of casting molds. The invention is intended for utilization in molding machines including a mold compressing unit wherein sand contained in molding flasks is compressed during the mold forming procedure.
With increasing mechanization of the techniques and devices utilized for the production of casting molds in foundries, there has occured a substantial increase in the size of the molding boxes or flasks which are utilized. This has resulted in a considerable increase in the necessity for rigidity of the molding boxes or flasks. Due to the compression methods which are utilized, higher compressive forces can be achieved interiorly of the molding flask. However, this has resulted in greater pressure upon the inner walls of the molding flask during the sand compressing operation thereby, in turn, requiring much greater rigidity and stability of the molding flasks.
Presently known techniques and devices available for stiffening or stabilizing the configuration of the molding flasks do not always meet the optimum requirements for production of an acceptable casting mold. In extensive tests it has been found that partially inadmissable deformations occur particularly during the molding of patterns having a large volume. The causes of these deformations have been found to be a lack of rigidity or stability in the shape of the molding boxes when under high compressive forces applied to the molding sand.
Attempts at providing strengthing or stabilization of the configuration of the molding boxes or flasks have at times resulted in an unacceptable increase in the weight of the flask. This is undesirable from many aspects. Apart from the higher production costs which may be involved in such weight increase, there occurs a requirement for correspondingly larger dimensions in other parts of the molding machine, such as conveyor tracks, turning and covering devices, and the like which must be adapted to the larger and heavier molding flasks.
Accordingly, the need exists for insuring that the molding boxes or flasks may retain sufficient rigidity of stability of form without incurring the disadvantages which arise with prior art devices.
The present invention is directed toward providing such a device wherein the geometric form of the molding box or flask may be maintained stable both before, during and after the compression of the casting mold to be produced.